Slitaz on USB / persistent

Hello everyone, I'm new to Slitaz, but not linux in general (been using Mint off and on for a number of years). While Mint has worked well for me, it is large for the limited time I spend in my linux partition. Slitaz seems like a good starting point, but this time around, I'd like to be able to run it/keep it on a USB rather than using harddrive space.
I've been reading about ways to make Slitaz on the USB persistent, but nothing has worked for me. When booting using the gui menu, I append the first option with "home=usb". I boot fine and get into the OS. I then make changes (add packages, etc). When finished, I've tried "tazusb writefs" and "tazusb writefs gzip". Neither seems to capture/save the OS with the changes. (next time I boot, it's reverted to the as d/l version)
The main reason I need to make the changes persistent is that I have a Lenovo T61 I'd like to run this with, but need to set up things like the appropriate Nvidia drivers (as per the fantastic writeup on here). I'd rather set things up once and then have the settings saved. I don't need the USB to boot with the persistent option every time, as once it's set up, I likely won't need to make a lot of changes going forward.
If anyone could give me a hand in trying to figure this out, it would be very much appreciated! I am using the latest ver 4 RC2 cooked.
Thanks!

home=usb is the same as home=sda1 which is why it only works if there are no hard drive's connected to the computer your running the tazusb on.
If a sata drive is connected, it will always be recognized before the usb drive and grabs sda.
I prefer to use UUID instead of /dev/sdXX as it locks /home to the unique UUID number of the flash drive.
Boot into slitaz and as root run:
#fdisk -l
You should be able to identify the flash drive by it's smaller size,number of partitions,filesystem,etc...
Now run:
#blkid
Edit your boot code so home=UUID

I have no sata drives connected to the computer,only a dvd writer so my USB flash is /dev/sda and home=usb could work in this configuration. But if I run my tazUSB in another computer with sata drives or add a sata drive to this computer it will mount the wrong partition as /home and not work correctly. None of the configs in my ~/ would be available,and if I tazusb writefs gzip the new rootfs will be written to the sata drive and not the tazusb drive.
My taz liveusb:
1. USB flash drive partitioned/formated to ext3 with Applications/System Tools/Gparted Partition Editor
2. Slitaz-4.0-RC2 live cdrom in drive
3. Applications/System Tools/Create a LiveUSB which is gui frontend for tazusb gen-liveusb and tazusb gen-iso2usb

mojo, thank you very much for the quick and detailed reply. I tried it last night and it does work. Guess I missed the step of creating a LiveUSB install.
Persistence works, now to try and get the graphic card working....